<script setup lang="ts">
import { computed, ref, watch } from 'vue';

// 定义水果对象的类型
interface Fruit {
  id: number
  icon: string
  isChecked: boolean
  num: number
  price: number
}

// 默认的水果列表
const defaultList = ref<Fruit[]>([
  {
    id: 1,
    icon: 'https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/ll.png',
    isChecked: true,
    num: 2,
    price: 6,
  },
  {
    id: 2,
    icon: 'https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/smt.png',
    isChecked: false,
    num: 7,
    price: 20,
  },
  {
    id: 3,
    icon: 'https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/tg.png',
    isChecked: false,
    num: 3,
    price: 40,
  },
  {
    id: 4,
    icon: 'https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/xg.png',
    isChecked: false,
    num: 10,
    price: 3,
  },
  {
    id: 5,
    icon: 'https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/yl.png',
    isChecked: false,
    num: 20,
    price: 34,
  },
],) 

// 如果持久化中没有存储数据，才读取默认值，如果有数据，就使用持久化的。
const fruitList =
  localStorage.getItem('List') === null ?// 是否有初始值，null 表示本地存储没有值
    ref<Fruit[]>(defaultList.value) // 没有值，初始化 ref 默认数据
    :
    ref<Fruit[]>(JSON.parse(localStorage.getItem('List') || '[]'))// 有值，就读取本地存储，JSON.parse 转对象

// 监听 fruitList 数组的变化
watch(fruitList, () => { 
  localStorage.setItem('List',JSON.stringify(fruitList.value))
},{deep:true})

//累加
const add = (id: number) => { 
  // 当 fruitList 变化时，将更新后的数组存储到本地存储中，JSON.stringify 转字符串后再存储
  const fruit = fruitList.value.find(item => item.id === id) as Fruit
   fruit.num++
}

//递减，控制按钮禁止也可以用disable设定条件
const jian = (id: number) => { 
  const fruit = fruitList.value.find(item => item.id === id) as Fruit
  if (fruit.num > 1) {
    fruit.num--
  } else { 
    alert('不能再减了哦')
  }
}

//删除
const Delete = (id:number) => { 
  fruitList.value=fruitList.value.filter(item=>item.id!=id)
}

//选择
const Select = computed({
  //获取计算结果，结果需要通过return返回
  get() {
    return fruitList.value.every(item=>item.isChecked)
  },

  //修改结果
  set(value) {
    fruitList.value.forEach(item=>item.isChecked=value)
  }
  
})

//结算总价
const money = computed(() => { 
  return fruitList.value.reduce((acc, item) => {
    if (item.isChecked) {
      return acc + item.price * item.num
    } else { 
      return acc
    }
  }, 0)
})

//结算总个数
const num = computed(() => { 
  return fruitList.value.reduce((acc, item) => {
    if (item.isChecked) {
      return acc + item.num
    } else { 
      return acc
    }
  }, 0)
})
</script>

<template>
  <div class="app-container" id="app">
    <!-- 顶部banner -->
    <div class="banner-box"><img src="https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/sg_top.png" alt="" /></div>
    <!-- 面包屑 -->
    <div class="breadcrumb">
      <span>🏠</span>
      /
      <span>购物车</span>
    </div>
    <!-- 购物车主体 -->
    <div class="main" v-if="fruitList.length">
      <div class="table" >
        <!-- 头部 -->
        <div class="thead">
          <div class="tr">
            <div class="th">选中</div>
            <div class="th th-pic">图片</div>
            <div class="th">单价</div>
            <div class="th num-th">个数</div>
            <div class="th">小计</div>
            <div class="th">操作</div>
          </div>
        </div>
        <!-- 身体 -->
        <div class="tbody">
          <div class="tr active"  v-for="item in fruitList" :key="item.id">
            <div class="td"><input type="checkbox" v-model="item.isChecked" /></div>
            <div class="td"><img :src=item.icon alt="" /></div>
            <div class="td">{{ item.price }}</div>
            <div class="td">
              <div class="my-input-number">
                <button class="decrease" @click="jian(item.id)"> - </button>
                <span class="my-input__inner">{{ item.num }}</span>
                <button class="increase" @click="add(item.id)"> + </button>
              </div>
            </div>
            <div class="td">{{ item.num * item.price}}</div>
            <div class="td"><button @click="Delete(item.id)">删除</button></div>
          </div>

        </div>
      </div>
      <!-- 底部 -->
      <div class="bottom">
        <!-- 全选 -->
        <label class="check-all">
          <!-- 双向绑定计算结果 -->
          <input type="checkbox"  v-model="Select" />
          全选
        </label>
        <div class="right-box">
          <!-- 所有商品总价 -->
          <span class="price-box">总价&nbsp;&nbsp;:&nbsp;&nbsp;¥&nbsp;<span class="price">{{ money }}</span></span>
          <!-- 结算按钮 -->
          <button class="pay">结算( {{ num }} )</button>
        </div>
      </div>
    </div>
    <!-- 空车 -->
    <div class="empty" v-else>🛒空空如也</div>
  </div>
</template>

<style scoped>
@import './assets/inputnumber.css';
@import './assets/index.css';
</style>